Load engaging mechanism of industrial lift truck



D. A. HARRIS July 12, 1966 LOAD ENGAGING MECHANISM OF INDUSTRIAL LIFT TRUCK 2 Sheets-Sheet 1 Filed Dec. 16 1963 DONALD A. HARRIS lA/VE/VTOI? BUCKHO/Ml, BLORE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS D. A. HARRIS July 12, 1966 LOAD ENGAGING MECHANISM OF INDUSTRIAL LIFT TRUCK 2 Sheets-Sheet 2 Filed Dec. 16 1963 DONALD A. HARRIS lNVENTOR BUCKHO/TW, BLORE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS United States Patent 3,260,392 LOAD ENGAGING MECHANISM OF INDUSTRIAL LIFT TRUCK Donald A. Harris, Vancouver, Wasln, assignor to Hyster Company, Portland, 0reg., a corporation of Nevada Filed Dec. 16, 1963, Ser. No. 330,354 13 Claims. (Cl. 214-652) This invention relates to improvements in the load engaging mechanism of an industrial lift truck. More particularly, the invention relates to improvements in a suction type load engaging mechanism of an industrial lift truck.

In a lift truck having a suction type load engaging mechanism, it is necessary for the sealing member of the suction head of the mechanism to have full contact with the load at the time of picking up a load, to enable a subatmospheric pressure to be created in the head. Thus, it is necessary that the position of the head conform to that of the load, and yet for the head to be stabilized after the load is picked up and during travel of the truck from place to place.

In the application of John E. Olson entitled Vacuum Type Load Handling Apparatus, Serial No. 246,629, filed December 21, 1962, now Patent No. 3,207,348, there is disclosed an industrial lift truck having a suction head mounted for self-adjusting movement to enable it to adjust its position to that of a load. The head is so mounted that after the load is picked up, the head is stabilized in a manner to resist wobbling movement thereof.

It is a main object of the present invention to provide a truck having a load engaging mechanism which is selfadjusting to enable it to adjust its position to that of a load, and which self-adjustment occurs under light contact pressure with the load, and which mechanism is stabilized in an even better manner than is the device of the above mentioned application.

A further object of the invention is to provide such a mechanism particularly adapted to pick up two rolls of paper, or other loads, and which is operable when the rolls are picked up to cause them to swing inwardly into contact with one another for better load stabilization.

Another object of the invention is to provide a selfadjusting load engaging mechanism of the type above described in which the dead weight of the suction head is counterbalanced so that there is minimum contact pressure with the load, so that the wear on the sealing member of the head is held to a minimum.

A more specific object of the invention is to provide a self-adjusting load engaging mechanism having an upright shaft so connected to the head, that the head is permitted to adjust its position to that of the load rapidly and easily.

Various other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a plan view of a front portion of a lift truck having a load engaging mechanism of the present invention;

FIG. 2 is a side view in elevation of the structure in FIG. 1, shown on an enlarged scale;

FIG. 3 is a vertical sectional view taken along line 33 of FIG. 1, FIG. 3 being on the same scale as FIG. 2;

FIG. 4 is a horizontal sectional view taken along line 44 of FIG. 3;

FIG. 5 is a horizontal sectional view taken along line 5--5 of FIG. 3;

FIG. 6 is a view similar to FIG. 4, but showing the vacuum head prior to engagement with a load;

head prior to engagement with a load;

ice

FIG. 8 is a diagrammatic view showing the manner in which a suction head is self-adjusting; and

FIGS. 9 and 10 show a modified form of the invention.

Referring particularly to FIGS. 1, 2 and 8, the truck 11 has a mast 13 at the front end thereof which is tiltable back and forth under the influence of a tilting mechanism 15 (FIG. 2). Guided for vertical movement along the mast 13 is a load carriage 17 which is raised and lowered by a suitable power means such as, for instance, a hydraulic ram 19 (FIG. 1). Supported by the carriage 17 is a suction pickup mechanism of the present invention which is shown as picking up paper rolls R and R in FIG. 1, whereas only a single roll R is shown in the diagrammatic view of FIG. 8. The invention, however, is not intended to be limited to picking up paper rolls.

The suction mechanism as shown in FIGS. 1 and 2, includes a pair of suction heads H and H which are brought into engagement with the load, in this case the rolls R and R whereupon a subatmospheric pressure is created within the heads through hoses 18 to enable them to pick up the load. The hoses 18 lead to a source of vacuum on the truck much as in the manner shown in application Serial No. 246,629, previously referred to.

It is apparent from FIGS. 1 and 2 that the positions of the heads must conform to that of the rolls to insure a proper fit of each head against its roll, or else a vacuum can not be drawn. The mechanism of the present invention so mounts the heads that they are self-adjusting and can adjust their positions to that of the load, under light contact pressure, when brought into engagement with the load.

Before going into a detailed description of the mechanism, reference will be made to FIG. 8 which shows certain critical features of the mechanism of my invention. The mechanism includes an upright shaft S which is mounted for turning movement about its own axis and has a pair of cranks C and C secured to its opposite ends and projecting in opposite directions from the shaft. It is evident that these directions are in transverse relation to the truck and are generally parallel to the plane of the mast 13. The outer or free end of each crank is pivotally connected at P to the head H in FIG. 8, with the upper crank C being connected to the upper portion of the head H and the lower crank C being connected to the lower portion of the head.

A spring, to be described, urges the shaft S to turn in such a direction that when the head H is unloaded (not carrying a load) it will assume a predetermined position relative to the mast 13, which position is shown in solid lines in FIG. 8. If the mast is vertically disposed, as shown in FIG. 8, the undoaded head H will be slightly rearwardly inclined, with the lower portion of the head disposed forwardly of the upper portion thereof. The inclination of the head is exaggerated in FIG. 8 for clarity in illustration.

As the head H approaches the load, with the mast and head so disposed, the lower portion of the head will first contact the roll R. The resulting contact pressure will force the lower portion of the head rearwardly to pivot the crank C rearwardly. Such pivoting movement will cause the crank C to pivot forwardly to thrust the upper portion of the head H forwardly to cause the head to assume the broken line position shown, that is, a position in vertical conformity with the position of the load R. It is further pointed out that both the pivots P and rotation of the vertical shaft permit the head to rock from side to side to enable it to properly conform to the position of the load R in a lateral direction.

As the suction head is elevated to elevate the roll R, the weight of the roll R will pivot the crank C forwardly and pivot the crank C rearwardly. This movement of the cranks will cause them to engage a pair of stops, not

shown in FIG. 8, to stabilize the load against movement about the axis of shaft S. Other means are used to stabilize the head against pivoting movement about the pivots P.

Now for a more detailed description, reference will be made to FIGS. 1 to 5, where the carriage 17 is shown as having a forwardly projecting bracket structure 41 (FIG. 1). A frame 43 is pivotally mounted at its center at 45 to the bracket structure to enable pivoting movement of the frame about a vertical axis. This will enable the load engaging mechanism to pivot so that the heads H and H can properly engage two rolls despite the fact that one roll is positioned further forwardly from the truck than the other. Stop lugs 46 on the frame limit pivoting movement of the frame.

The frame 43 is shown as including spaced upper and lower arm members 47 and 49 (FIG. 3) connected by a web 51. The frame is indented in a vertical direction (FIG. 1) at the central portion thereof so that the rolls R and R will be disposed as close to the mast 13 as possible.

The suction heads H and H are of identical construction so that the detail description of the construction of one will suffice. Head H includes a suction cup member 51, which is curved about a vertical axis. The cup member may be of the articulated type shown in the copending application of John E. Olson, Serial No. 268,257, filed March 27, 1963, entitled Vacuum Head Construction and Method or it may be of the plain or unarticulated type. In any event, the cup member has an elastomer sealing member 52 around the peripheral margin of the cup member for engaging a load and forming a seal therewith.

At the upper portion of the rear side thereof, the cup member has two spaced pairs of ears 53, and at its lower portion has two spaced pairs of cars 55. A pair of bent arms 57 and 59 are connected by pivots 61 to the ears, and if the cup member is articulated, one end of each arm is slotted to provide for articulation of the cup memher.

The upper arm 57 is pivotally connected by a universal joint 63 (FIG. 3) to an upper crank 65 intermediate the ends of the latter, while the arm 59 is pivotally connected by universal joint 67 to an end portion of a lower crank 69. Cranks 65 and 69 are rigidly secured to the ends of an upright shaft 71 (FIG. 3) which is rotatably mounted on one set of end portions of the arm members 47 and 49 of the frame 43. It is apparent from FIGS. 3 to that the upper end of the shaft 71 is connected to an end of the crank 65, while the lower end of the shaft is connected to an intermediate portion of the crank 69. As shown in FIG. 3, the cranks 65 and 69 project in opposite directions from the shaft toward the universal joints 63 and 67, respectively. Thus, the joints establish a tilting axis 70 for the cup member, which axis is oblique to the axis of the shaft 71, and is askew relative to the periphery of the cup member 51.

Upper crank 65 projects to the left, as the parts are shown in FIG. 4, beyond the joint 63 to provide a stop engaging portion 65a for engaging a stop 81. The stop is fixed to the upper arm member 47. Lower crank 69 also projects to the left to provide a stop engaging portion 69a for engaging a stop 83 which is fixed to the lower arm member 49 (FIG. 3).

A center line, labeled (E, is provided in FIGS. 4 and 5 and extends through the axis of the shaft 71 in each figure and 69 to the shaft 71 and the stops 81 and 83 is such that, as the parts are shown in FIGS. 4-7, a rearward movement of the upper portion of the cup member 51 will cause the upper crank 65 to move away from the stop 81. This will turn shaft 71 in a clockwise direction to swing the lower crank 69 away from its stop, to move the lower portion of the cup member forwardly. In fact, any movement either forwardly or rearwardly which is imparted to either the upper or lower portion of the cup member will cause an opposite movement of the other portion. As will be shown hereinafter, when the cup member is unloaded, the cranks are spaced from the stops 81 and 83, as shown in FIGS. 6 and 7, so that the cranks are free to turn in either direction so that it does not matter whether the upper portion or the lower portion of the cup member first engages the load.

The adjusting movement of the vacuum cup 51 permitted by the shaft 71 and its cranks is genera-11y in a vertical, longitudinal plane of the truck. It is also pointed out that the vacuum cup can pivot on the universal joints 63 and 67 about the axis 70 to permit the cup to properly face the roll. or other load. in a lateral direction.

Since the center of gravity of the cup member 51 is forwardly of the axis of the shaft 71 (FIG. 4), even when the cup member is unloaded, the dead weight of the cup member will urge the cup member to tilt forwardly to bring the upper crank against its stop 81 and cause the lower crank 69 to engage its stop 83. In fact, since the cup member 51 has substantial weight, it would require a not inconsiderable force to move the upper part of the cup member rearwardly.

To make the cup member self-adjusting under a light contact pressure with the load, the cup member is counterbalanced by a coil spring 91 (FIG. 3) which is secured at its opposite ends of the shaft and the web 51. The spring is sufficiently stressed so as to counterbalance the cup member so that the cup member, when unloaded, is in a balanced condition and requires very little force to move it one way or the other. In fact, the stress in the spring is preferably such that when the cup member is unloaded, the spring will cause the cranks 65 and 69 to assume positions separated from their stops 81 and 83, respectively, as shown in FIGS. 6 and 7. In these positions of the cranks, the vacuum cup member is selfadjusting regardless of whether its upper or lower portion first contacts the load.

If desired, the stress in the spring 91 can be adjusted so that the cranks remain in light contact with their stops even when the cup is unloaded, as shown in FIGS. 9 and 10. With this arrangement, it is important that the cup member be arranged so that its upper portion will first engage the load, because if the lower portion first engaged the load, the force applied against the lower portion would only press the lower crank against its stop with an increased pressure, without effecting any adjustment of the position of the cup member.

Preferably the shaft 71 is divided into two tubular sections 71a and 71b which are connected by a torsion bar 716. Thus, if the manufacturing and assembly tolerances are such that when one crank is against its stop, the other crank is slightly spaced from its stop, rather than being in contact with such stop, the shaft can twist under load to enable the latter crank to also contact its stop. It is pointed out that the torsion bar could be eliminated by providing a shaft and frame sufliciently sturdy to stand up under the stresses imposed thereon by the load, even though only one crank is against its stop, but the form of the invention shown in FIGS. 6 and 7 is preferredi Now, turning to FIGS. 1 and 3, it is apparent that the axis through the universal joints 63 and 67 of head H is inclined upwardly to the left, as the parts are shown in FIG. 3. The construction of the head H is such that the axis through its universal joints will extend upwardly to the right so that the two axes extend upwardly in a converging relationship.

Since the center of gravity of the two suction cups of heads H and H and the center of gravity of the loads carried by these cups is disposed forwardly of the askew axes of the heads H and H it is apparent that both cups will tend to pivot inwardly toward one another so that the rolls R and R will be brought into engagement with one another to stabilize the load against pivoting movement about such askew axes. It is pointed out that the stops 81 and 83 in no way interfere with pivoting movement of the suction cup members about such askew axes and in fact the only limitation on such pivoting movement is the contact of such suction cup members with the arm members 47 and 49 of the frame 43.

It is further pointed out that even with a single suction head, a stabilized condition of the load in a lateral direction will be effected by the oblique nature of its askew axis, because the load will cause the cup member to pivot into engagement with frame 43 (which thus functions as a stop) so that the cup member is stabilized against free wobbl'ing movement in a lateral direction. This pivoting movement of the cup member and load serves to locate the center of gravity of the load closer to the front wheels of the truck. In such location, the load adds to the stability of the truck during travel of the truck from place to place. 7

Having described the invention in what is considered to be the preferred embodiment thereof, it is desired that it be understood that the invention is not to be limited other than by the provisions of the following claims.

Iclaim:

1. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure, mounting means mounting said suction cup member on said carniage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith,

said mounting means including an upright shaft mounted for turning movement about its axis,

two cranks secured one to each of the opposite ends of said shaft,

said cranks extending generally parallel to the plane of said mast and transversely of said truck and projecting in opposite directions from said shaft,

I each crank being pivotally connected to said head, with such connections being on the opposite sides of and spaced from said shaft.

2. In a lift truck having a mast and a carriage struc ture movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure,

mounting means mounting said suction cup member on said carriage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face to-face contact therewith,

said mounting means including an upright shaft mounted for turning movement about its axis,

two cranks secured one to each of the opposite ends of said shaft, said cranks extending generally parallel to the plane of said mast and tnansversely of said truck and projecting in opposite directions from said shaft,

universal joints means pivotally connecting each crank to said suction cup member,

and stop means to limit turning movement of said shaft.

3. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure, mounting means mounting said suction cup member on said carriage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith,

said mounting means including an upright shaft mounted for turning movement about its axis,

6 two cranks secured one to each of the opposite ends of said shaft, said cranks extending generally parallel to the plane of said mast and transversely of said truck and projecting in opposite directions from said shaft, universal joints means pivotally connecting each crank to said suction cup member, stop means to limit turning movement of said shaft, and means for engaging said cup member to limit pivoting movement thereof about an axis extending through said joints. 4. In a load engaging mechanism having a pair of upright suction cup members for engaging a pair of separate loads, first mounting means mounting one cup member for pivoting movement about a first upright axis, second mounting means mounting said other cup :mem-

ber for pivoting movement about a second upright axis, said upright axes being oblique to the vertical and converging in an upward direction so that said cup members are urged by the force of gravity to swing in directions to bring into engagement the loads carried thereby whereby to stabilize said loads, further mounting means for each cup member mounting each cup member for tilting movement about a transverse axis whereby said cup members can conform their positions to that of the loads to be carried thereby, and means for limiting such tilting movement about such transverse axes, each further mounting means including an upright r0- tary shaft carrying a crank on each end thereof, the cranks extending generally parallel to a plane which is normal to the direction in which the associated cup member faces, said cranks being connected to said cup member at places disposed on opposite sides of said shaft. 5. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure, mounting means mounting said suction cup member on said carriage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith, said mounting means including an upright shaft mounted for turning movement about its axis, two cranks secured one to each of the opposite ends of said shaft, said cranks extending generally parallel to the plane of said mast and transversely of said truck and pro jecting in opposite directions from said shaft, each crank being pivotally connected to said head, with such connections being on the opposite sides of and spaced from said shaft, said cup member being dis-posed forwardly of said shaft so that the force of gravity urges said cup member to tilt in a forward direction, and oounterbalancing spring means urging said shaft in a direction opposite to the direction it is urged by the Weight of said cup member so that said cup member will adjust its position under light contact pressure with said load. 6. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure, mounting means mounting said suction cup member on said carriage structure in generally a vertical position and for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith, said mounting means including an upright shaft mounted for turning movements about its axis,

two cranks secured one to each of the opposite ends of said shaft in spaced relation with respect to one another, said cranks extending generally parallel to the plane of said mast and transversely of said truck and projecting in opposite directions fro-m said shaft, means pivotally connecting each crank to said suction cup member, stop means for each crank, to limit turning movement of said shaft, means for effecting engagement between said cranks and stop means in the loaded condition of said cup member, said cranks and thus said stop means being spaced from one another by a distance at least greater than onehalf the height of said cup member so that such substantial spacing insures that the cup member will be stabilized against a tendency to float in the loaded condition of said cup member. 7. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure, mounting means mounting said suction cup member on said carriage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith, said mounting means including an upright shaft mounted for turning movement abouts its axis, two cranks secured one to each of the opposite ends of said shaft, said cranks extending generally parallel to the plane of said mast and transversely of said truck and projecting in opposite directions from said shaft, universal joints means pivotally connecting each crank to said suction cup member, stop means for each crank engageable therewith to limit turning movement of said shaft, said shaft having a reduced portion intermediate its ends so that said shaft may twist under a load to assure engagement of both cranks with their stop means. 8. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure, mounting means mounting said suction cup member on said carriage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith, said mounting means including an upright shaft mounted for turning movement about its axis, two cranks, sh-aft means mounting said cranks for pivoting movement on said carriage structure in spaced parallel relation with respect to one another, means pivotally connecting each crank to said suction cup member, stop means for each crank, means to cause said crank to move toward said stop means when said cup member is loaded, said shaft means being flexible under torsional stresses an extent such as to enable both cranks to be in concurrent engagement with said stop means even though in the absence of such flexing only one stop would engage its stop means leaving the other stop means spaced therefrom an appreciable though small extent. 9. A load engaging mechanism for a lift truck comprising,

a suction cup member for engaging a load, mounting means for mounting said cup member on a load carriage for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith,

said mounting means including an upright shaft mounted for turning movement about its axis,

two cranks secured one to each of the opposite ends of said shaft,

said cranks extending generally parallel to a plane which is normal to the direction in which said cup member faces,

universal joint means pivotally connecting each crank to said suction cup member,

stop means to limit turning movement of said shaft,

and means for engaging said cup member to limit pivoting movement thereof about an axis extending through said joints.

10. In a lift truck having a mast and a carriage structure movable along said mast,

a suction cup member for engaging a load disposed forwardly of said carriage structure,

mounting means mounting said suction cup member on said carriage structure for self-adjusting movement to enable said member to adjust its position to that of the load for face-to-face contact therewith,

said mounting means including an upright shaft mounted for turning movement about its axis,

two cranks secured one to each of the opposite ends of said shaft,

said cranks extending generally parallel to the plane of said mast and transversely of said truck and projecting in opposite directions from said shaft,

each crank being pivotally connected to said head, with such connections being on the opposite sides of and spaced from said shaft,

stop means for each crank,

said cup member being disposed forwardly of said shaft so that the force of gravity urges said cup member to tilt in a forward direction to move said cranks toward said stop means,

and counterbalancing spring means urging said shaft in a direction opposite to the direction it is urged by the weight of said cup member so that said cup member will adjust its position under light contact pressure with said load,

said counterbalancing spring means .being of sufficient strength so that in the unloaded condition of said cup member, said cranks will be spaced from said stop means so that said cup is floating and may fieely adjust its position to that of a load which it contacts.

11. In a lift truck having an upright mast and a carriage movable along said mast,

an upright forwardly directed suction cup disposed forwardly of said carriage,

mounting means connected to said carriage for mounting said cup, said mounting means being rotatable at its connection to said carriage about a first upright axis,

universal joint means connecting said cup to said mounting means at points on laterally opposite sides of said first upright axis establishing a second upright axis oblique to said first upright axis,

said oblique axis being swingable relative to said first upright axis upon rotation of said mounting means such that pivoting of said mounting means about said first axis enables both a forwardly and rearwardly tilting movement of the upper and lower portions of said cup, and a lateral pivoting movemnet of said cup so that said cup can conform its position to that of a load upon engagement with said load.

12. A lift truck having a front end, a rear end, an upright mast at said front end, and a carriage movable along said mast,

a pair of suction heads disposed in front of said carriage,

means mounting each said suction head on said carriage for universal movement prior to engaging a load so that said heads are caused to conform their positions to those of a pair of loads upon engagement with said loads,

said means establishing a first vertical shaft means about which one of said heads can swing,

means including a vertical shaft mounitng said suction head on said carriage,

means mounting said vertical shaft'for swinging movement about its axis,

said means establishing a second vertical shaft means 5 means pivotally mounting said suction head to said verabout which the other of said heads can swing, tical shaft at positions on laterally opposite sides of said means establishing a third axis oblique to said first said shaft establishing a second axis oblique to the vertical shaft means about which said one head can axis of said shaft, so that said cup is caused to conswing, I form its position to that of a load upon engagement said means establishing a fourth axis oblique to said 10 with a load,

second vertical shaft means about which said other and stop means limiting swinging movement of said head can swing, shaft about its axis without limiting rotation of said means limiting swinging movement of said heads about head about said oblique axis so that upon picking up their respective vertical shaft means without preventa load said head is caused to swing by gravity in a ing swinging movement of said heads about th ir 15 predetermined transverse direction about said obrespective oblique axes so that upon picking up a load ique aXis 0 a ta iliz d p sition. said heads are caused by gravity to swing about said oblique axes but are prevented from swinging about References Cited by the Examiner their vertical shaft means, UNITED STATES PATENTS 31231 5 2;attains,assassinas;

. 2,850,279 9/1958 Stoothoff 294-64 X said heads are caused to swing 1nwardly about the1r 2 853 333 9/1958 ittell 29464 oblique axes toward the longitudinal centerline of 2 979 523 3/1960 cushman said truck until said loads are mutually engaged and said cups thereby stabilized 25 2942745 6/1960 Horton 214*650 3,089,723 5/1963 Fortson.

13. A lift truck having a front end, a rear end, an upright mast at said front end, and a carriage movable along said mast,

a suction head disposed in front of said carriage,

GERALD M. FORLENZA, Primary Examiner.

MORRIS TEMIN, Examiner. 

11. IN A LIFT TRUCK HAVING AN UPRIGHT MAST AND A CARRIAGE MOVABLE ALONG SAID MAST, AN UPRIGHT FORWARDLY DIRECTED SUCTION CUP DISPOSED FORWARDLY OF SAID CARRIAGE, MOUNTING MEANS CONNECTED TO SAID CARRIAGE FOR MOUNTING SAID CUP, SAID MOUNTING MEANS BEING ROTATABLE AT ITS CONNECTION TO SAID CARRIAGE ABOUT A FIRST UPRIGHT AXIS, UNIVERSAL JOINT MEANS CONNECTING SAID CUP TO SAID MOUNTING MEANS AT POINTS ON LATERALLY OPPOSITE SIDES OF SAID FIRST UPRIGHT AXIS ESTABLISHING A SECOND UPRIGHT AXIS OBLIQUE TO SAID FIRST UPRIGHT AXIS, SAID OBLIQUE AXIS BEING SWINGABLE RELATIVE TO SAID FIRST UPRIGHT AXIS UPON ROTATION OF SAID MOUNTING MEANS SUCH THAT PIVOTING OF SAID MOUNTING MEANS ABOUT SAID FIRST AXIS ENABLES BOTH A FORWARDLY AND REARWARDLY TILTING MOVEMENT OF THE UPPER AND LOWER PORTIONS OF SAID CUP, AND A LATERAL PIVOTING MOVEMENT OF SAID CUP SO THAT SAID CUP CAN CONFORM ITS POSITION TO THAT OF A LOAD UPON ENGAGEMENT WITH SAID LOAD. 